The Program in Biostatistical Science fosters fundamental and targeted research into the mathematical and computational questions in statistical science that arise in cancer research. We believe that the strongest interaction between clinical, biological, population and statistical scientists occurs in an environment in which faculty statisticians both conduct research in statistical methodology and work closely with scientists from other disciplines. As a result, the program supports a wide range of interdisciplinary research and collaborative projects in which statisticians serve as principal or co-principal investigators and hold leadership roles in national and international clinical trials groups and population-based consortia. The specific aims of the program are: 1. To develop new methodology in statistical science and computational biology that responds to emerging areas of cancer research. This research includes methods for the analysis of genomic and molecular biology investigations of cancer, such as gene and protein expression arrays, along with methods for the design and analysis of modern clinical trials, screening studies, and observational and population-based studies and for investigations of genetic predisposition of diseases. 2. To develop statistical software and programming environments for the analysis of new genomic assays as they become available and are used in studies of cancer. 3. To provide training and research mentoring for students wishing to begin careers as statisticians in cancer research. Training of minority students is a major focus. There are approximately 610 cancer-related program member publications in the last grant period, with 14% of them being intra-programmatic, 50% of them being inter-programmatic, and 39% of them being interinstitutional. The Program in Biostatistical Science has 32 members from six institutions (HSPH, DFCI, MGH, BWH, BIDMC, HMS). These members are affiliated with two departments at HSPH (Biostatistics and Epidemiology) and four departments at HMS (Medicine, Health Care Policy, Pediatrics, Radiation Oncology). The total NCI and other peer reviewed support for the last budget year was $7,470,789.